Dear Lord, what a mess.
Do yours look like this?
If so that's all too common (hey, once is too much, right?), the ball seat "sticks" and the shaft breaks off above it.
You might see if you can find the proper length of the newer design that the ball seat is cast as part of the bolt head.
Snap-on has some pretty expensive "universal" sockets that have squarish little teeth, if you found one in the close size and pounded it on the end of the bolt with a sledge it might hold enough for you to get it out of there. Otherwise the drill method Kajtek1 mentioned is about it.
My sincerest sympathies.
Take care and enjoy the ride,
Greg